1. FFA Dairy Foods Career Development Event
Types and Causes of Milk Off-Flavors
Developed by Student - Danny Rice, 2006

2. Milk Off-Flavors Information
Milk of excellent quality possesses a characteristically milk flavor and odor.
Milk that is sampled should be at a temperature of 60 degrees Fahrenheit. Very cold or very warm milk is difficult to evaluate.
A separate cup should be used to taste each sample.
Precautions should be taken that students are not allergic to materials used to create off-flavors.

3. Acid Off-Flavor
Milk that has developed some acidity as a result of bacterial growth will have a detectable acid flavor even before it is classified as sour. Buttermilk can be used to give the acid flavor.

4. Bitter Off-Flavor
A bitter taste in fresh milk may be caused by strong feeds or weeds which may carry through into the milk. Bayer asprin or quinine sulfate can give the bitter taste to the milk sample to give the bitter off-flavor.
Use a very, very, very tiny amount of quinine sulfate - if you use it.

5. Feed Off-Flavor
The feed a cow eats may impart certain flavors to milk. Some stronger feeds will carry through more noticeably than will others. Green grass, silage and alfalfa are good examples. Strained silage or molasses can be used to create the off-flavor of milk.

6. Flat/Watery Off-Flavor
The source of this uncommon flavor is difficult to determine. The flavor may be described as tasteless. Flat-flavored milk resembles normal milk that has been partially diluted with water.
Thus, water may be used to produce the flat/watery off-flavor.

7. Foreign Off-Flavor
Any seriously objectionable flavor foreign to milk such as fly spray, paint, oil, kerosene, creosote or medicinal substance will render the milk unpalatable. Residue from sanitizers could be absorbed and be left as foreign flavor. Clorox bleach may be used to create the off-flavor.

8. Garlic or Onion Off-Flavor
This obnoxious weed flavor, imparted to milk when the cow eats garlic or onions is not classified as one of the usual feed flavors. This recognizable odor and flavor could render the milk undesirable for use. Using garlic salt can be used to produce the off-flavor.

9. Malty Off-Flavor
Malty is not a common flavor but may be encountered if not properly cooled. Certain bacteria from improperly cleaned equipment may contaminate the milk and cause the malty flavor. Grape-nuts cereal may be used to develop the off-flavor.

10. Oxidized Off-Flavor
This flavor can produce quite a pungent flavor in the advanced stages. It develops when milk placed in a glass or plastic container remains in the sun for a period of time. It can also be produced if the milk comes in contact with copper or iron. Soaking pennies in milk will can produce the oxidized off-flavor.

11. Rancid Off-Flavor
This off-flavor resembles the flavor of stale fat produced by the enzyme lipase causing a change in composition of the milk fat. Extreme agitation of warm milk in the presence of air causes foam and the rancid flavor within a few hours. Homogenized milk can be used to create the flavor.

12. Salty Off-Flavor
Salty taste may be produced from cows in late lactation possibly infected with mastitis. This defect cannot be detected by odor but taste alone. Plain table salt may be used to produce the off-flavor.

13. Dairy Foods Off-Flavor Resources
Instructional Materials Services
Texas A&M University
Larry Lyder
Hill City Agriculture Education/FFA Advisor